Sorry for the double post, but I needed to bump this thread. Also if anyone hasn't figured out how to unlock the other 2 zombie maps, "Five" and Dead Ops Arcade then here's a tutorial.
1. Go to Main Menu.
2. Look down at your hands. ( IN GAME )
3. Rapidly press the left and right triggers.
4. Go behind the chair to the computer and hold down whatever it tells you ( X for Xbox ) to access the computer.
5. Type in on the computer 3ARC UNLOCK and then click ENTER.
6. Go to zombie mode and select either one of the maps.
7. ????
8. PROFIT
